"Characterization of a Type II Metallothionein from Helianthus Annuus U" by Sridhar Bhogavalli

Date of Award

2007

Degree Type

Thesis

Department

Chemistry

First Advisor

Wei, Robert

Subject Headings

Metallothionein, Common sunflower

Abstract

Metallothioneins (MTs) are ubiquitous low molecular weight, cysteine rich proteins with a pronounced affinity for metal ions with d10 configuration such as Cu, Cd and Zn. These heavy metals form metal-thiolate clusters with cysteine side chains. In contrast to the vertebrate forms, knowledge about the properties of members of the plant metallothionein family is still scarce. We describe here a method of isolation and purification of metallothionein from the plant Helianthus annuus, performed by affinity chromatography using glutathione-agarose column. In this study, alignment of gene sequence of the isolated H. annuus metallothionein cDNA with known MTs showed that it belongs to the type 2 of the plant MTs. The gene sequence encoding MTs was cloned into a suitable vector and the protein was overexpressed in Escherichia coli. The purified metallothionein was evaluated by SDS-PAGE and characterized by UV spectra of the apo-and metal bound protein. Detection of metal bound protein was also carried out by using chemiluminescence assay. The metal binding ability of metallothionein was evaluated by 5, 5 dithio (2-nitrobenzoic acid) (DTNB) analysis. The affinity of metal ions for metallothionein was in the order of Cu>Cd>Zn

Included in

Chemistry Commons

COinS